These investigations concern myocardial adaptation to stress in the rat. The stress initially used is that of pressure overloading of the left ventricle by banding of the ascending aorta. Studies have been accomplished investigating the myocardial responses to the pressure overloading the moderately and severely diabetic state as well as in alcoholism. In these states the degree of hypertrophy was similar to that in the control animal. Studies are continuing by investigating isoproterenol cardiomyopathy in the diabetic animal.